Teach Yourself Borland C++ in 14 Days - portal

Using the Debugger
macros, TRACE and WARN, allow you to do exactly that. These macros are convenient debugging
tools that many programmers overlook because of sparse documentation and general lack of
discussion on the subject.
When you use TRACE or WARN in your programs, the messages produced by these macros go
to a log file called OutDbg1.txt. C++Builder automatically creates this text file and displays
it in a Code Editor window whenever a TRACE or WARN statement is encountered. You can then
browse the log file to see what has happened in your program.
NOTE
NOTE
The OutDbg1.txt file has a couple interesting characteristics. For
one, the file is not considered part of the project. When you do a Save
All, the OutDbg1.txt file is not saved as the rest of the files in the project
are. Along those same lines, when you close the OutDbg1.txt file, you
are not prompted to save the file. If you want the file saved, you must
specifically do a Save or Save All prior to closing it.
This might seem a little odd, but it makes sense when you think about
it. The log file is almost always used as a temporary debugging tool.
Rarely do you need to save the contents of the log file, so by not
prompting you to save the file, C++Builder saves you the aggravation of
having to deal with another message box.
The TRACE macro simply outputs a line of text to the log file in the Code Editor. For example,
you might have the following code in your FormCreate() function:
void __fastcall TMainForm::FormCreate(TObject *Sender)
{
TRACE(“Entering FormCreate()”);
// intialization code
TRACE(“Leaving FormCreate()”);
}
When this code is executed, two lines will be written to the OutDbg1.txt file. You can view
the messages in the log file at any time—either during program execution or after the program
terminates—simply by clicking on the OutDbg1.txt tab in the Code Editor.
The diagnostic macros make use of C++ streams (remember when we
used those way back on Day 1, “Getting Your Feet Wet”?). This makes
it possible to create log messages like the following:
TRACE(“Varible x = “